1. Field of the Invention
This invention relates to a connector device and EGR sensor having the same and, more particularly, to the structure of a terminal plate to be insert-molded in a housing of a synthetic resin.
2. Description of the Related Art
Conventionally, the gasoline-engine-mounted vehicle or the like has an EGR system for recycling part of emission gas toward the air intake, in order to reduce the NOx amount in emission gas. The EGR system has an EGR sensor in order for controlling the recycling amount of emission gas toward the air intake.
The EGR sensor, as shown in FIG. 6, is structured mainly with a housing 101 made of a synthetic resin, a cover 102 provided on an aperture of the housing 101, an operating shaft 103 slidably arranged to the cover 102 and having an outer end abutted against a not-shown EGR valve, a return spring 104 provided in the housing 101 and always urging the operating shaft 103 outward, a slider receiver 105 provided at an inner end of the operating shaft 103, a slider 106 attached to the slider receiver 105, a resistance board 107 provided in the housing 101 and for sliding the slider 106, a signal-transmission terminal plate 108 made of a metal having an intermediate part insert-molded in the housing 101 and one end connected to the resistance board 107, and a power-feed terminal plate 109 made of a metal having an intermediate part insert-molded in the housing 101 and both ends projecting outward of an end surface of the housing 101.
The power-feed terminal plate 109 is structured with a wide portion 109a and a narrow portion 109b, as shown in FIGS. 7A, 7B and 7C. The wide portion 109a and the narrow portion 109b are formed in respective constant widths. The wide portion 109a, at its tip, is formed with a slit 109c for inserting therein a terminal member (not shown) provided on one mating connector device. The narrow portion 109b, at its tip, is formed with a chamfer 109d for easy insertion to a terminal member (not shown) provided on the other mating connector device.
The power-feed terminal plate 109 is bent rectangular at a point of the narrow portion 109b close to the wide portion 109a, whereby insert-molding is made by a housing 101 in a range shown at the arrows in FIG. 7C.
In the meanwhile, in case the power-feed terminal plate 109 made of a metal is insert-molded by the synthetic-resin housing 101, cure contraction of the synthetic resin causes sink mark in the synthetic resin on the main and back surfaces of the power-feed terminal plate 109 as shown in FIG. 8, thus causing a clearance 110 between the power-feed terminal plate 109 and the housing 101. The clearance 110 has a width-a nearly equal to a width of the power-feed terminal plate 109 and a height-b increasing in proportion to the width of the terminal plate 109. Incidentally, FIG. 8 is a widthwise sectional view of the power-feed terminal plate 109.
The EGR sensor especially requires high air-tightness because there is a pressure of the emission gas being recycled from the exhaust pipe to air-intake pipe of the gasoline engine, exerted at a side set up with the cover 102 and operating shaft 103.
However, the related-art EGR sensor is not applied by an art for suppressing or eliminating the clearance 110 formed between the power-feed terminal plate 109 and the housing 101, involving a problem of not having a practically sufficient air-tightness.
Incidentally, although the above exemplified the case of a clearance formed on the main and back surfaces of the power-feed terminal plate 109, similar trouble occurs also on the main and back surfaces of the signal-transmission terminal plate 108.
Meanwhile, although the above exemplified the EGR sensor, the foregoing trouble is not unique to the EGR sensor, similar problem exists on every connector device that pressure exerts on an insert-mold part of terminal plate.